Dissociative Electron Attachment to Jet Cooled Oxygen

Ramaprasad, Varun (2019) Dissociative Electron Attachment to Jet Cooled Oxygen. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Varun Ramaprasad (14MS051)) 14MS051.pdf - Submitted Version Restricted to Repository staff only Download (10MB)

Abstract

We have studied the electron attachment process with isolated oxygen molecules and small van der Waals clusters of oxygen formed in pulsed supersonic jet of oxygen molecules. Electron capture by an effusive oxygen beam is known to produce a resonance at 6.5 eV incident electron energy following the reaction.In our study, we have a clear observation of two distinct resonance peaks at ~11 and ~16 eV incident electron energies along with the 6 eV peak, from O⁻ and O₂⁻ ions formed by dissociative electron attachment to a pulsed supersonic jet of O₂ molecules seeded in a beam of argon containing (O2)n clusters Our supersonic expansion setup used for the experiment reduces the cost of the experiement by avoiding a catcher chamber and an extra pump at the orifice, which was otherwise essential in all previous experiments. Formation of small oxygen clusters in such a setup is reported here for the first time. The characteristics of the molecular jet can be completely explained if we know the translational beam temperature and the Mach number. By converting the time-of-flight spectra to a velocity distribution, and fitting this velocity distribution with the equation governing supersonic jets, we can obtain both T and M. In this thesis, we have demostrated this excercise for O⁻ ions in a jet of O₂ with O₂:Ar ratio 1:10. The same analysis can be extended to different ratios and our results provide further impetus to study the same

Actions (login required)

View Item